An acid-base buffer in a solution that lessens the impact on pH
from the addition of acid or base. The small amount of
H3O+ or added to an un-buffered solution
changes that the pH by several units. Because of the logarithmic
nature of pH, this change is several orders of magnitude larger
than the change that results from the same addition to a buffered
solution. To with stand the addition of strong acid or strong base
without significantly changing its pH, a buffer must contain an
acidic component that can react with the ion and a basic component
that can react with added H3O+ ion.